The invention relates generally to a method for doping impurities into semiconductor device layers and more particularly, the invention relates to a solid phase diffusion method for doping impurities into semiconductor device layers.
Currently, doped areas in wafers are created in one of a few ways. In one method, a semiconductor layer is grown with the dopant impurity in the gas stream during epitaxial growth of the semiconductor layer. The wafer can then be patterned and etched leaving doped regions. Epitaxy is typically conformal and non-selective.
In another method, a pattern is made on a wafer or on top of an epitaxially grown layer. Impurities are then ion implanted by controlling the dose and power. Although ion implantation can be selectively performed, it often leaves a damaged matrix and requires a subsequent annealing process to embed the dopant impurity within the matrix.
A method for doping impurities without the drawbacks of the current techniques would therefore be desirable.